1. Field of the Invention:
This invention relates to an improved conduit gripping tool, such as a packer or hanger, for use in subterranean wells, and a running tool and method for installing the hanger in the well.
2. Description of the Prior Art:
In the completion or workover of any subterranean oil or gas well, it may be necessary to install one or more packers or hangers to accomplish various well known operations that are required for the completion of the well. For example, a hanger is generally mounted at a position immediately above a production formation to permit the installation of a screen and the subsequent gravel packing of such screen and adjacent portions of the production formation. Packers and/or bridge plugs are also required to be set in gripping engagement with the casing at various points along the casing bore.
All conventional packers and hangers which are mechanically set in gripping engagement with the casing have heretofore required two successive or sequential rotational movements in opposite directions, one of which is the same direction as the hand of the threaded connections of the tubular work string by which the packer or hanger is inserted and installed in the well, and the other rotation is in the reverse direction. One of such rotations is required to effect the release of the hanger or packer setting mechanism preliminary to the application of a downwardly directed setting force to the packer or hanger. The second rotational movement is normally required to effect the release of the running tool from the packer or hanger after setting is accomplished, so that the running tool and work string may be withdrawn from the well.
The primary reason that the prior art mechanisms for initiating setting of the casing gripping tool and the subsequent release of the running tool therefrom required two opposite rotations of work string, is that the known hanger or packer mechanisms were incapable of distinguishing between the rotational movements applied thereto to confine the effects thereof to merely the preliminary setting operation or the subsequent releasing operation of the running tool. It has therefore become the standard practice to employ a left hand rotation of the work string and running tool to initiate the setting of the hanger or packer, and then use a right hand rotation of the work string and running tool to effect the release of the running tool from the packer or hanger after the setting thereof. Obviously, anytime that a left hand rotation is applied to a right hand threaded tubular work string, there is the danger that the unthreading of one of the multitude of pipe sections will occur, rather than the transmission of the rotational force to the running tool located at the bottom of the threadably interconnected work string.
It therefore becomes highly desirable that both the setting initiation rotation of the running tool and the releasing rotation of the running tool be in the same direction, and that this direction be the same as the hand of the threaded connections of the tubular work string. In other words, in the ordinary situation, where right hand threads are used to make up the tubular work string, two sequential right hand rotations of the work string and running tool are preferred to effect the release of the packer or hanger for setting and the subsequent release of the running tool from the packer or hanger.